If you can find a employer to sponsor H1b before your OPT expires, you can change to H1. The question is when you can get a job. It takes 3-8 months to get H1b status after you get the job offer.
As soon as you file I485 with your spouse, you file for EAD. It take 2-3 months to get EAD. You can keep your non-immigrant status as long as you don't use EAD. You'd better not use EAD until your spouse's I140 is approved, which takes 6-24 months.